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Excited states in the extremely neutron-deficient isotope 172Hg have been established for the first time. The 96Ru(78Kr,2n) reaction was employed to populate excited states in 172Hg with a cross section σ ≈ 15 nb. The highly selective Recoil-Decay Tagging (RDT) technique was used to obtain clean in-beam γ-ray spectra for 172Hg. The yrast ground-state band has tentatively been established up to I = 6h. The data have been interpreted within the framework of total Routhian surface and quasiparticle random phase approximation calculations. In addition to the well-known features of shape coexistence previously observed in light Hg isotopes, the systematic trends in the energy of the yrast 2+ and 4+ states in the chain of Hg isotopes indicate a pronounced vibrational collectivity which is reduced in strength, but at the same time shows a higher degree of harmonicity, as the neutron number decreases below the neutron midshell. [ABSTRACT FROM AUTHOR]

Gamma-ray transitions have been identified for the first time in the extremely neutron-deficient Tz = 1 nuclide 110Xe and the energies of the three lowest excited states in the ground-state band have been deduced. A level scheme has also been constructed for the proton-unbound, Tz = 3/2 nuclide 109I, exhibiting band structures built on g7/2 and h11/2 states in a weakly deformed, triaxial nucleus. In addition, a third band is proposed to be built on a g7/2 orbital coupled to an octupole-vibrational phonon of the 108Te core. The results were obtained in a recoil-decay tagging experiment using the 58Ni(54Fe,2n/p2n) reaction at a beam energy of 195 MeV. The experiment was performed using the highly efficient JUROGAM γ-ray spectrometer in conjunction with the RITU gas-filled recoil separator and the GREAT focal-plane spectrometer. The results on 110Xe establish a breaking of the normal trend of increasing first excited 2+ and 4+ level energies as a function of decreasing neutron number as the N = 50 major shell gap is approached for the neutron-deficient Xe isotopes. This unusual feature is suggested to be an effect of enhanced collectivity, possibly arising from isoscalar n-p interactions becoming increasingly important close to the N = Z line. Features in the low-lying levels of 106Te and 109I, showing similar trends, are also discussed. [ABSTRACT FROM AUTHOR]

Preliminary lifetime values have been measured for a number of near-yrast states in the odd-A transitional nuclei 107Cd and 103Pd. The reaction used to populate the nuclei of interest was 98Mo(12C,3nxα)107Cd, 103Pd, with the beam delivered by the tandem accelerator of the Wright Nuclear Structure Laboratory at an incident beam energy of 60 MeV. Our experiment was aimed at the investigation of collective excitations built on the unnatural parity, ν h11/2 orbital, specifically by measuring the B(E2) values of decays from the excited levels built on this intrinsic structure, using the Doppler Recoil Distance Method. We report lifetimes and associated transition probabilities for decays from the 15/2- and the 19/2- states in 107Cd and the first measurement of the 15/2- state in 103Pd. These results suggest that neither a simple rotational or vibrational interpretation is sufficient to explain the observed structures. © 2006 American Institute of Physics [ABSTRACT FROM AUTHOR]

Gamma-ray transitions from excited states in 106Te have been identified using the recoil decay tagging technique. The experiment which was the reaction 54Fe(54Fe,2n)106Te* was performed at the JYFL accelerator facility at the University of Jyväskylä, Finland. The production cross section was estimated at 25 nb, a new limit for in-beam γ-ray spectroscopy. A tentative level structure for the ground state band of 106Te is proposed. © 2006 American Institute of Physics [ABSTRACT FROM AUTHOR]